Blood-collection device

ABSTRACT

The invention relates to a device for receiving bodily fluids, comprising a collection tube ( 1 ), whose front end is equipped with a domed section ( 7 ) with a pierceable stopper for an attachable guide sleeve ( 2 ), which on the side facing the domed section has a cannula ( 5 ) equipped with a rubber valve ( 3 ) and on the side facing away from the domed section has a connecting piece or the front section of a double cannula. The domed section ( 7 ) has a zone that can be deformed inwards and the exterior wall of the domed section in said zone and/or the interior wall of the guide sleeve ( 2 ) in a complementary zone have or has a projecting contour in relation to the remaining exterior zone of the domed section ( 7 ) and/or in relation to the remaining interior zone of the guide sleeve ( 2 ), said contour deforming the wall of the domed section ( 7 ) radially inwards, when the deformation-resistant guide sleeve ( 2 ) is attached. The domed section and the guide sleeve form in their combined usage position a non-positive fit, whose retaining force is greater than restoring force of the rubber valve ( 3 ).

The invention relates to a device for drawing body fluids, having aspecimen tube having at an outer end a tip with a pierceable plug for aguide sleeve fittable on the tip and provided on its side turned towardthe tip with a needle and with an elastomeric needle-shield tube and onthe side turned away from the tip with a connection fitting or theopposite end of a double needle.

Such devices are for example used for drawing blood from a bottle or bagor to take a specimen from a connection vessel of for example urine. Inevery case there is the problem that the elastomeric needle-shield tubethat surrounds the needle and that is collapsed like a bellows when theguide sleeve is fitted to or installed on the tip exerts a substantialsprint return force acting against the forces that retain the guidesleeve on the tip, with the result that the guide sleeve is pushed offthe tip. In order to get around this problem, various measures aretaken.

In the blood-drawing device described in German 3,049,503, the capclosing the outer end of the specimen tube has a cylindrical axiallyextending tip. The tip is closed at its outer end by a pierceable plugthat is trapped between an inner centrally apertured wall of the tip andan outer-end rim. The tubular guide sleeve, that has on its outer end aholder for a double-ended and pointed needle whose outer end is intendedfor insertion into a vein while its inner end projects fo far into theguide sleeve that when the guide sleeve is fitted to the specimen tubeit pokes through the plug, is axially shiftable and rotatable on thetip. The inner end of the needle projecting from the guide tube iscontained in a bag-like tube (elastomeric needle-shield tube) of suchlength that the inner point of the needle does not initially reach toits closed end.

In order that the guide sleeve stays on the tip in spite of the springpressure from the elastomeric needle-shield tube the tip is providedwith a laterally projecting bump for holding the double-ended needlethat fits in an angled slot in the guide sleeve. This holding bumpprojecting over the slot in the periphery forms a sort of bayonet latchthat secures the guide sleeve to the double needle. Such a latch ensuresa solid connection of the fitted-together parts of the blood-drawingdevice, but increase it s production cost. In addition the coupling anddecoupling or latching of the guide sleeves requires that the holdingbump first be aligned by turning of the specimen tube with the closingscrew or plug cap to align with the slot, which requires some adeptmanipulation so that the parts can be properly aligned.

German 692 25 609 describes a protective housing for a needle screwedinto a needle holder. Here the protective housing is rotatable on theholder to which end the protective housing has a ring forming aninwardly open groove in which a ridge on a tip of the holder fits.

It is an object of the invention to provide a device of theabove-described type with a simple and reliable connection for the twointerfitting parts that can be produced at low cost, is easy to use, andprovides a solid enough retention to resist the spring force (returnforce) of the needle-shield tube tending to open it.

This object is achieved by a first embodiment with the features of claim1, by a second embodiment with those of claims 2, and by anotherembodiment with those of claim 3.

All embodiments recognize the basic idea that for example standardretaining formations facility a grip of the guide sleeve and the tip ofthe plug or screw cap, but do not provide a solid seat, either too tightor too lose, between the two fitted-together parts of the device so thatone does not get an acceptable connection hold when coupling to ordisconnecting from a specimen tube. This problem is cured by the systemof this invention when for example in a starting position beforeinstallation of the guide tube, the tip has in what will be itsconnection at least one retaining formation (such as a longitudinal rib,ridge, bump, or the like) or is of outwardly convex or barrel shape orthe inner surface of the guide sleeve (see claim 2) is appropriatelyshaped, or both such systems are used, or there is a lesser wallthickness or a softer material so that when the hard and rigid guidesleeve is slipped into places the radially projecting retainingformation or the projecting shape exerts radially inwardly effectingelastic forces that are also applied to the guide sleeve such that theguide sleeve is retained against the return or spring forces on the tip.

In further embodiment according to the invention the retainingformations projecting outward from the surface of the tip are deformedelastically to the side in that the longitudinal ribs or for exampleclosely juxtaposed bumps or short webs or similar formations are pushedabout their longitudinal axes laterally and angularly fo the tip. Thusin spite of the relative small diameter of the interfitting parts (guidesleeve and tip) the desired self-locking hold is achieved, the partsfitting together more easily and with less resistance and similarlyseparating more easily than a standard tapered luer connection.

The gripping that is the result of the deformation of the tip or theshape of the tip near its retaining formations or the projecting outershape and/or the guide sleeve as a result of the lateral deflection ofthe retaining formations from their normal positions or the deflectedretaining formations with prestress is such that the return forceexerted the needle-shield tube does not push off the guide sleeve. Thetemporary radial deformation caused by the diameter relationships eitherof the tip or the lateral deflection of the holding formations caused bythe rigid guide sleeve can be set by appropriate selection of materialsand dimensioning with respect to size and elasticity.

There is thus always an interaction between a rigid guide sleeve withthe tip and a diameter difference between these two parts such that inthe connection region there is a solid enough grip. This is ensured inthat the tip is made elastically deformable, for example by using anappropriate plastic and/or dimensioning its wall thickness such that itswall deflects radially inward when the guide sleeve is fitted to it. Theover sizing and deflection of the elastically yielding tip ensures thatno matter what the inside diameter of the guide sleeve which has forexample longitudinal ribs, a ridge, or a local raised part, is smallerthan the outside diameter of the tip that is thus cylindrical and isdeflected inward by the strength of the guide sleeve. On the other handwhen the retaining formations deflect laterally, the tip and the guidesleeve are both rigid and nondeformable.

Further embodiments and particular features of the invention are seen inthe claims and the following description of embodiments of ablood-drawing device according to the invention as shown in the drawing.Therein:

FIG. 1 is an exploded view of a specimen tube with a guide sleeve;

FIG. 2 is an overall view of the guide tube fitted over the tip of thespecimen tube of FIG. 1;

FIG. 3 is an exploded view of another embodiment of the specimen tubeand guide sleeve;

FIG. 4 is a section taken along line IV-IV of FIG. 3;

FIG. 5 is an overall view of the guide tube fitted over the tip of thespecimen tube of FIG. 3; and

FIG. 6 is a section taken along line VI-VI of FIG. 5.

A blood-drawing device according to FIGS. 1 and 2 comprises a specimentube 1 with a tip 7 or 107 and a guide sleeve 2 provided in allembodiments for example with a luer fitting and holding a needle 5having a point 4 and surrounded by an elastomeric shield tube 3. Inother embodiments of the guide sleeve, its side turned away from the tiphas a connector or the outer part of a double needle. The guide sleeve 2is made of a rigid hard plastic. The specimen tube 1 is closed at itsupper end by a cap 9 that has the cylindrical tip 7. It has in thisembodiment a plurality of retaining formations 8 provided spaced aboutits periphery on its outer surface, here shaped as longitudinal ribsthat start about in the middle of the tip and go to its inner end.Alternatively the holding formations can be for example rows of closelyspaced bumps or the like or similar formations on the outside surface ofthe tip and/or the inside surface of the guide sleeve, for exampleeither convex or concave. In the connection region provided with thisshape or these retaining formations 8 the diameter is oversize, that isthe outside diameter of the tip 7 is larger than the inside diameter ofthe guide sleeve 2. Such an oversized diameter between the guide sleeve2 and tip 7 is also provided when in a manner not shown here the insidediameter of the guide sleeve is partially smaller than the outsidediameter of the tip.

To draw blood the guide sleeve 2 and the specimen tube 1 are pushedtogether, that is the rigid guide sleeve 2 is slid onto the tip 7 of thecap 6. At first the end of the elastomeric shield tube 3 engages theplug set in the tip 6. On further pushing-together, the shield tube 3collapses like a bellows (see FIG. 2) and is pierced by the inner needlepoint 4 which then pokes through the plug so that the point 4 is exposedinside the specimen tube. Once the rigid guide sleeve 2 is in its endposition of FIG. 2 in contact with the retaining formations 8 (herelongitudinal ribs), the guide sleeve 2 will bear radially inward via theretaining formations 8 on the elastically deformable wall of the tip 2and deform it radially inward into a waisted shape as shown in FIG. 2.The guide sleeve 2 is thus held with prestress solidly on the tip 7 ofthe cap 6.

This holding effect is also present when, according to the embodiment ofFIGS. 3 to 6 where reference numerals from the described embodiment areapplied to corresponding structure, the tip 107 retains its originalshape when fitted with a rigid guide sleeve 2 and instead the retainingformations or longitudinal ribs 108 are constructed such that theydeflect when the guide sleeve 2 is fitted in place, for example pushingangularly to the side of the tip against its surface and away from theinner surface of the guide sleeve, that is pivoting about theirlongitudinal axes 9 as shown in FIGS. 5 an 6. The tip 107 is here rigidlike the guide sleeve 2 while the retaining formations 1208 areelastically resilient.

The embodiments of FIGS. 1 and 2 an 3 to 6 have in common that withoutany change in the inside diameter of the guide sleeve as it is fittedover the cap as a result of the material it is made of and itsdimensions with the retaining formations relative to the guide-sleeveinside diameter and the over sizing of the tip when unstressed, there iseither a radial inward deformation of the tip in the connection regionof the retaining formations deflect laterally. The necessary holdingforce can also be obtained when the inside diameter of the rigid guidesleeve is slightly smaller than the outside diameter of the tip so thatits walls also must deflect inward or the dom is provided with a convexshape (e.g. rounded or barrel-shaped).

1. A device for drawing body fluids, the device comprising a specimentube (1) having at an outer end a tip (7) with a pierceable plug for aguide sleeve (2) fittable on the tip (7) and provided on its side turnedtoward the tip (7) with a needle (5) and with an elastomericneedle-shield tube (3) and on the side turned away from the tip with aconnection fitting or the outer end of a double needle, characterized inthat the tip (7) has an inwardly elastically deformable region and theouter surface of the tip in this region and the complementary innersurface of a rigid guide sleeve (2) have relative to the rest of theouter surface of the tip (7) and the rest of the inner surface of theguide sleeve (2) such a shape that on mounting of the rigid guide sleeve(2) the wall of the tip (7) deforms radially inwardly, a connectionbeing formed between the fitted-together tip and guide sleeve that isstrong enough than return force of the shield tube (3).
 2. A device fordrawing body fluids, the device comprising a specimen tube (1) having atan outer end a tip (7) with a pierceable plug for a guide sleeve (2)fittable on the tip (7) and provided on its side turned toward the tip(7) with a needle (5) and with an elastomeric needle-shield tube (3) andon the side turned away from the tip with a connection fitting or theouter end of a double needle, characterized in that the tip (7) has aninwardly elastically deformable region and the inner surface of a rigidguide sleeve (2) has relative to the rest of the inner surface of theguide sleeve (2) such a shape that on mounting of the rigid guide sleeve(2) the wall of the tip (7) deforms radially inwardly, a connectionbeing formed between the fitted-together tip and guide sleeve that isstrong enough than return force of the shield tube (3).
 3. A device fordrawing body fluids, the device comprising a specimen tube (1) having atan outer end a tip (107) with a pierceable plug, the tip (107) having onits outer surface at least one radially projecting retaining formation(108) for a guide sleeve (2) fittable on the tip (107) and provided onits side turned toward the tip (107) with a needle (5) and with anelastomeric needle-shield tube (3) and on the side turned away from thetip with a connection fitting or the outer end of a double needle,characterized in that the tip (107) including at least one of itsretaining formations (108) is oversized in a connection region relativeto an inside diameter of a rigid guide sleeve (2) and the retainingformations (108) is constructed such that on fitting of the rigid guidesleeve (2) it deflects laterally and in a fitted-together use positionof the guide sleeve (2) and tip (107) the holding force is greater thanthe return force of the shield tube (3).